Tetracyclic anthraquinone antibiotics, in particular doxorubicin and daunorubicin, are widely used anticancer drugs. Doxorubicin has significant curative effects on lots of solid tumors including liver cancer, gastric cancer, breast cancer, lung cancer, ovary cancer and various leukemias. Daunorubicin is one of the most effective drugs for treating leukemia. However, due to their side effects such as severe myelosuppression, cardiac toxicity, adverse responses in digestive tracts and the like, their clinical applications are somewhat restricted. Up to now, lots of derivatives of tetracyclic anthraquinones have already been separated from the nature or artificially synthesized.